Cutter position compensating mechanism for profiling machines



May 29, 1956 H. ERNST ET AL CUTTER POSITION COMPENSATING MECHANISM FORPROFILING MACHINES 6 Sheets-Sheet 1 Filed May 10. 1954 1 T TORNE Y8.

May 29, 1956 H. ERNST ET AL CUTTER POSITION COMPENSATING MECHANISM FORPROFILING MACHINES 6 Sheets-Sheet 2 Filed May 10, 1954 INVENTOR.

HANS ERNST HANS FR/TSCH/ ywm ATTORNEYS.

May 29, 1956 H. ERNST El AL CUTTER POSITION COMPENSATING MECHANISM FORPROFILING MACHINES 6 Sheets-Sheet 3 Filed May 10, 1954 a; Ii .4

R. HA/vs ERNST HANS FRITSOHI 3V ZWZMIM Z /44 ATTORNEYS.

OR PROFILING MACHINES May 29, 1956 H. ERNST ET AL CUTTER POSITIONCOMPENSATING MECHANISM F 6 SheetsSheet 4 Filed May 10, 1954 /60 /57 H4H5 f lgpl f'ig.fl 5

m7fii 4 w /07 SO ma Q g Q 79 mfg 70 J *K F m5 /6 m2 fjlg 25K /0/ l7 /7HANS ERNST l6 By HANS FR/TSCH/ Fig l 5 g ,13 ATTORNEYS.

May 29, 1956 H. ERNST ET AL 2,747,459

CUTTER POSITION COMPENSATING MECHANISM FOR PROFILING MACHINES Filed May10, 1954 6 Sheets-Sheet 5 A97 A92 277 Z/B //7 INVENTOR.

HANS ERNST I73 BY HANS FR/TSCH/ A T TORNEYS.

May 29, 1956 H. ERNST El AL 2,747,469

CUTTER POSITION COMPENSATING MECHANISM FOR PROFILING MACHINES Filed May10, 1954 s Sheets-Sheet a 58W 2Q, 59 F1 g .1 5

I l I \1 Z 7 96 v a f 83 w IN V EN TOR.

HANS ERNST BY HANS FH/TSCH/ fl T TORNE YS.

ljnited States Patent O CUTTER POSITION COMPENSAT IN G MECHANISM FORPROFILING MACHINES Hans Ernst, Cincinnati, and Hans Fritschi, ArnherleyVi!- lage, Ohio, assignors to The Cincinnati Milling Machine Co.,Cincinnati, Ohio, a corporation of Ohio Application May 10, 1954, SerialNo. 428,752

17 Claims. (Cl. 90-13) This invention relates to automatic profilingmachines and more particularly to a new and improved mechanism forcompensating the position of the cutter in accordance with defiectivemovements of the tracer finger whereby the cutter and tracer finger willmore nearly contact corresponding points on the work and patternthroughout a profiling operation.

In modern practice the desire for higher feed rates in profilingoperations has led to greater inaccuracies in reproduction because thecutter is in fixed relation with respect to the tracer support, whilethe end of the defiective tracer finger has a degree of movementrelative to the end of the cutter, with the result that the two do notstay exactly in contact with corresponding points on the work andpattern at all times throughout a profiling operation. Furthermore, thisdegree of relative movement is necessarily increased with increases inthe feed rate. A particularly undesirable situation arises in internalprofiling operations when the tracer finger enters a square corner andhits a wall at right angles to its direction of feed. The patternengaging end of the tracer finger is naturally stopped by the wall,while its support continues to move in the feed direction carrying thecutter with it. Before the corrective deflection can be imparted to thetracer to institute a change in the direction of feed, the cutter hasover-traveled and removed more material than it should. The faster thefeed rate, the greater the inertia to be overcome, resulting in greateroverrun and greater damage, as well as inaccuracy.

One of the objects of this invention therefore is to provide anadjustable mounting for the cutter spindle similar to the adjustablemounting of the tracer finger and automatically impart compensatingmovements to the cutter in conformity with defiective movements of thetracer finger so as to more nearly maintain the finger and cutter incontact with corresponding points on the pattern and work throughout atracing operation.

Another object of this invention is to provide automatic tracer controlof the cutter compensating movements.

A further object of this invention is to provide in conjunction with arotary tracer head having an eccentric tracer finger, a rotary controlhead for an eccentric cutter spindle coupled for simultaneous rotationwith the tracer head to maintain orientation of both members in theplane of feed regardless of variations in direction of said plane asactuated by the pattern.

Still another object of this invention is to provide new and improvedmechanism for a profiling machine in which the cutter as well as thetracer finger are eccentrically positioned with respect to their normalfixed axes on a common support, and to automatically rotate the tracerfinger and the cutter about these fixed axes to maintain them orientedin the direction of feed, and to automatically reduce the eccentricityof the cutter whenever the eccentricity of the tracer is automaticallyreduced by the pattern.

7 2,747,469 Patented May 29, 1956 Other objects and advantages of thepresent invention should be readily apparent by reference to thefollowing specification, considered in conjunction with the accompanyingdrawings forming a part thereof, and it is to be understood that anymodifications may be made in the exact structural details there shownand described, within the scope of the appended claims, withoutdeparting from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate likeor similar parts:

Figure 1 is a front elevation of a profiling machine embodying theprinciples of this invention.

Figure 2 is a plan view of the machine shown in Figure 1.

Figure 3 is a view on the line 3-3 of Figure 2 showing the completetracer controlled mechanism.

Figure 4 is a section on the line 4-4 of Figure 3.

Figure 5 is a section on the line 5-5 of Figure 3.

Figure 6 is a section on the line 6-6 of Figure 5.

Figure 7 is a section on the line 7-7 of Figure 3.

Figure 8 is a section on the line 8-8 of Figure 7.

Figure 9 is a section on the line 9-9 of Figure 8.

Figure 10 is a section on the line 10-10 of Figure 1.

Figure 11 is a section on the line 11-11 of Figure 1.

Figure 12 is a section on the line 12-12 of Figure 10.

Figure 13 is a section on the line 13-13 of Figure 10.

Figure 14 is a section on the line 14-14 of Figure 3.

Figure 15 is a view of the mechanism shown in Figure 14 as viewed fromthe right of that figure.

Figure 16 is a fragmentary section on the line 16-16 of Figure 12.

Figure 17 is a fragmentary section on the line 17-17 of Figure 13.

Figure 18 is a diagrammatic view of the hydraulic control circuit.

Figure 19 is a detail view of the hand wheel as viewed on the line 19-19of Figure 1.

Figure 20 is a detail section on the line 20-20 of Figure 19.

Figure 21 is a diagram of the eccentric shifting of the spindle in onedirection by the eccentric shown in Figure 4.

Figure 22 is a diagram of the eccentric shifting of the spindle in asecond direction by the eccentric shown in Figure 5.

Figure 23 is a diagram of the resultant shifting effected by botheccentrics.

In Figures 1 and 2 of the drawings there is shown a profiling machineembodying the principles of this invention, and its general constructionconsists of a bed or support 10 to which is secured a pattern 11 and awork piece 12 by any suitable well-known means. The bed 10 has alongitudinal guideway 13 formed along one side, and a secondlongitudinal guideway 14 formed along the other side for receivingslidable upright members 15 and 16 respectively. These uprights aresuitably tied together by a cross rail 17 which extends crosswise of thebed at a suitable distance above it, and which may be made integral withthe uprights. The cross rail has a motor 18 attached thereto foreffecting reciprocation of the uprights longitudinally of the bed, andthe motion transmitting mechanism for this purpose comprises a pair ofbevel gears 20, one of which is driven by the motor 18 and the other ofwhich is attached to a drive shaft 21. The drive shaft is supported onand extends parallel to the cross rail and has beveled gears 22 and 23suitably secured to opposite ends thereof.

The gear 22 drives, through a bevel gear 23', a vertical shaft 24,journaled in the upright 15 and terminating in a spur gear 25 whichmeshes with rack teeth 26 formed on the guide 13. Similarly, the gear 23meshes with a bevel gear 28 secured to the end of vertical shaft 29 3 tjournaled in the upright 16 and terminating in a spur gear which mesheswith a rack 31 formed on the guide 14. It will now be seen that rotationof the motor 18 will effect a feeding movement of the uprights and crossrail longitudinally of the bed 14) relative to the pattern and work. 7

Parallel to the cross rail 17 is a slide 32 supported on verticalguideways 33 and 34 formed on the up rights 15 and 16. This slide isvertically adjustable by a handwheel 34a on the end of shaft 34bjournaled in slide 32, which carries a pinion 34d meshing with a rack34c fixed on the upright 15. Mounted on the slide 32 is a saddle 35mounted on guides 35a and 355 formed on slide 32. It is driven by amotor 35c which has a gear 36 meshing with rack teeth 37 formed on theslide 32 whereby rotation of the motor will feed the saddle 35 relativeto the slide 32 and laterally across the bed 10. The saddle 35 has apair of longitudinally extending guideways 38 and 39 upon which areadjust ably mounted a tracer head mechanism 40 and a spindle carriermechanism 41. Thus a tracer and cutter on these mechanisms are movablelongitudinally of the pattern and work by the motor 18, and crosswise bythe motor 35c.

For accuracy of reproduction it will be understood that the spacing 42between the axis 43 of the rotary tracer head of mechanism 40, and theaxis 44 of the cutter spin dle of mechanism 41 should be equal to thespacing 45 between the axis 46 of the pattern 11, and the axis 47 of thework piece 12; and that the diameter of the tracer finger 48 shouldpreferably be equal to the diameter of the cutter 49. When theserelationships exist, it can be said that the tracer and cutter engagecorresponding points on the pattern and work respectively.

As shown in Figure 2, the axes 43 and 44 lie in a vertical plane passingthrough the axis 50 which is parallel to the direction of cross movementof the saddle 35. Therefore, in view of this relationship, the tracermechanism 40 and the cutter spindle mechanism 41 may be manuallyadjusted on the guideways 38 and 39 and secured thereto to establish thespacing 42 equal to the spacing 45. Thus, the mechanisms and the saddle35 are capable of movement in a unit crosswise of the pattern and work,and since all of these are carried by the uprights, they are alsomovable as a unit longitudinally of the pattern and work.

In order to facilitate the tracer action for high speed tracing, thetracer finger 48, shown in Figure l, is not supported co-axially withthe tracer head axis 43 shown in Figure 2, but is advanced relativethereto in the direction of feed having an eccentric adjustment. Due tothe nature and construction of the tracer mechanism utilized herein, anexternal profiling operation is efiected by feeding the tracer relativeto the pattern in a clockwise direction around the pattern. In otherwords, the tracer finger follows around the outside of a pattern in aclockwise direction, whereas in internal profiling operations the tracerfollows around the pattern in a counterclockwise direction. Since thepattern 11 requires an external profiling operation, the direction offeed is in the direction of the arrow indicated by the reference numeral51 in Figure 2, and therefore the tracer finger 48 is adjusted relativeto the center or axis 33 of the tracer head in the direction of thearrow 51 a predetermined amount, such as to the position indicated bythe reference numeral 52. The amount of this adjustment is representedby the reference numeral 53 and is greatly exaggerated for easyunderstanding. It will be obvious that when this adjustment has beenmade, the cutter 49 no longer contacts a point on the work corresponding to the point of contact of the tracer with the pattern.

Therefore, by means of this invention, the cutter 49 is also advanced inthe same direction and to the same extent, such as to the position 54.From then on, any change in the direction of feed, or in the distance'53 due to the backward deflection of the tracer finger, isautomatically com- 4. V pensated for by a similar change in the positionof the cutter relative to its normal fixed axis represented by the axis44. In order to further understand this invention, it is necessary firstto describe the construction of the tracer head. The rotary tracer headshown herein has the same basic principle of tracer action as that shownin our pending application, Serial No. 288,806, now Patent No.2,730,129, granted January 10, 1956, filed in the United States PatentOffice on May 20, 1952.

The tracer head mechanism 40 comprises a box-like frame 55 which issecured to the guideways 38 and 39 as shown in Figure 3. Fixed on theframe 55 is a cylindrical housing 56 having an upward extension 57forming a tracer valve housing, and a lower cylindrical extension 58housing a rotary tracer head 59, The rotary head 59 is journaled inanti-friction bearings 66 and 61 in its hous ing, and at the upper endcarries a bevel gear 62 meshing with a bevel gear 63 which is driven bya hydraulic motor 64. Rotation of the hydraulic motor is controlled by atracer valve mounted in the housing 57. It comprises a valve plunger 65reciprocaole in the valve sleeve 66 in which is formed a plurality ofcontrol parts for controlling reversible rotation of the motor 64.

The rotary head 59 has an eccentric shaft 67 journaled therein parallelto the axis of rotation of the head as shown in Figure 10 of thedrawings. A crank arm 69, Figures 3 and 11, is secured to the lower endof the shaft 67, and a second crank arm is secured to the upper end ofthe shaft. The lower crank arm 69 carries means for supporting thetracer finger 48, while the upper crank arm 70 is operatively connectedfor controlling the shifting of the tracer valve plunger 65. Thus, anylateral movement of the tracer finger 48 will transmit motion to thevalve plunger 65 through rotation of the shaft 67 relative to the rotarytracer head.

The lower crank 69 is keyed to the shaft 67 and held thereon by a nut79' threaded on the end of the shaft, as shown in Figure 3. The crank69, Figure 11, has a pair of spaced depending ears 71 which areconnected to opposite sides of block 72, pivotally supporting it bymeans of a cross pin 73 extending at right angles to the shaft 67. Thetracer finger 48 is provided with an integral flange 74 which is boltedto the block 72 by means of clamping screws 75 which pass throughenlarged holes 76 in the flange 74 whereby the axis of the tracer fingermay be cc centrically adjusted with respect to the axis of the tracerhead. This adjustment may be effected by a pair of set screws 77 and 78threaded in the block '72 engaging a square projection 79 formed on theupper end of the tracer finger 48. By means of this adjustment, the axis84 0f the tracer finger may be shifted relative to the axis 43 of thetracer head and normal to the axis of pin 73 a predetermined amountindicated by the reference numeral 82 and in the direction of feed. Thisis the eccentric adjustment previously referred to and is of aprescribed amount to which the cutter will also be adjusted as explainedhereafter. A compression spring 83 is mounted in sockets 84 and 85formed respectively in the block 72 and the crank arm 69 for effecting aclockwise rotational urge on the block 72 and tracer finger abouts itspivoted pin 73. This movement is limited by the following means whichacts as a positive stop to hold the tracer finger vertical.

The block 72 is provided with a laterally projecting arm 7 86 which, asshown in Figure 19, has a roller 37 attached thereto, and which engagesa locating surface 88 formed on the underside of the hand wheel 89 whichis secured to the bottom of the rotary tracer head 59. Thus. it will beseen that the spring 83 holds the parts in a definite rotationalposition about the pin 73 against the stop surface 88. The parts are soarranged that this locates the tracer finger 48 in a vertical positionwith its axis parallel to the axis of rotation of the tracer head andthe axis of rotation of the cutter.

The purpose of this oscillatable construction of block 72 is to causeoperation of a control valve to effect comenemas p'risation in theposition of the cutter in the event that the tracer finger should meet apositive abutment that would cause backward deflection of the tracerfinger, that is, rotation of the tracer finger 48 opposite to thedirection of feed about the pivot pin 73 in a counterclockwise directionas viewed in Figure 11.

This control valve is indicated generally by the reference numeral 90,in Figure 11, and comprises a valve plunger 91 which is pivotallyconnected at 92 to the end of a lever 93 which serves to support thevalve plunger and cause movement thereof. The lever 93 is pivotallyconnected at 94 to a projecting boss 95 formed on the inside of therotary tracer head 59. A connecting lever 96 is pivotally connected at97 to the lever 93 at a point approximately midway between the endsthereof, and the other end is pivotally connected at 98 to a stud 99projecting from the top of the block 72 and anchored therein by a setscrew 100. It will now be seen that when the tracer finger 43 isvertically positioned by the stop means just described that the valveplunger 91 will assume a definite position in its valve sleeve 101 andits ports formed therein and that when the tracer finger is backwardlydeflected, the valve will move down. The operation of this valve will bedescribed in connection with the cutter spindle compensating mechanism.

As shown in Figures 14 and 15, the tracer valve operating crank arm 70,which is secured to the upper end of the eccentric shaft 67, as shown inFigure 3, is provided with a roller 102 which engages a roller 103formed in 21 depending arm of a bell crank 104 which is pivotallysupported on a pin 105 mounted in a boss 106 formed on the tracer head59. The bell crank 104 has a second roller 107 secured to its other arm108 and positioned to engage the lower end of the tracer valve plunger65. It will now be seen that lateral movement of the crank arm '70, asviewed in Figure 14, will cause rotation of the bell crank 104 and causeaxial movement of the tracer valve plunger 65 which is held inengagement with the roller 107 by means of a spring 109 shown in Figure3.

Another spring 110 is connected at one end to a dependent arm 111 of thebell crank 104 and at the other end to a pin 112 fixed in the tracerhead 59. The object of this spring is to cause rotation of the crank 70and thereby of the shaft 67 and lower crank 69 in a clockwise directionas viewed in plan to continually urge the tracer finger 48 intoengagement with the pattern and maintain engagement therewith during thetracing operation.

The operation of the tracer mechanism during a tracing operation can bemore clearly understood from the diagram in Figure 23, where the axis 43of the tracer head forms a reference point for explanation of therelationship of the parts. With respect to the surface of the pattern 11to be followed, it will be noted that the tracer finger 48 is on oneside of the pattern line, while the axis of the shaft 67 is on the otherside of the pattern line. Thus, a line connecting axis 43 with the axisof shaft 67 is at an angle to the direction of feed 51, preferably about45 degrees. With the parts in this relation, the tracer valve is held ina central or neutral position, so that any lateral movement of thetracer finger 48 to the right or left of the axis of feed will open thetracer valve, either above or below its neutral position, and causerotationof the hydraulic motor 64 in one direction or the other andthereby corresponding rotation of the tracer head.

It will be noted, however, that the rotation of the tracer head is aboutthe axis 43, whereby the tracer finger and the shaft 67 will be movedclockwise or counterclockwise about said axis as a center and repositionthe tracer finger so that it always points in the direction of feed fromthe axis 43 and parallel to a tangent at the point of contact with thepattern.

This tracer action is independent of the other tracer action, whereinthe tracer is deflected backward about pivot 73 by a pattern wall, suchas one at right angles to d the direction of feed. This causes operationof valve plunger 91.

The tracer thus has two actions, one of which causes rotation of thetracer head to change the direction of feed in accordance with changesin the pattern, and the other, operation of the compensating controlvalve plunger 91. Both of these actions are transmitted to the cutterspindle mechanism to effect certain adjustments in the position of thecutter relative to its main support.

The hydraulic motor 64, besides causing a rotation of the rotary tracerhead, also causes rotation of the spindle head, and is connected by atelescoping shaft connection 64, as shown in Figure I to a rotaryservo-valve 113, which is hydraulically connected to cause rotation of ahydraulic motor 114 coupled in feed-back relation to the servo-valve113. The motor 114 drives through bevel gears 115 and 116, Figure 3, asecond rotary head 117 which is journaled in a fixed part of theframework 41. Since the tracer finger is laterally adjustable in ahorizontal plane with respect to the axis of the tracer head, the samekind of adjustment must be imparted to the cutter in order to maintainthe cutter in positional correspondence with the tracer. The rotary head117 operates to maintain this adjustment.

The cutter 49 is attached to the end of a cutter spindle 118 which isjournaled in a conventional manner in the cutter spindle quill orhousing 119, and attached to the upper part of this housing is anelectric motor for driving said spindle. The parts 119 and 120constitute a unit provided with a flange 121 by which the unit issecured to an anti-frictionally supported slide 122, shown in Figure 4,by suitable screws or bolts 123.

As shown in Figure 4, the slide 122 is supported by antifriction means124 in a second slide 125, which is supported by anti-friction means 126in a fixed part 127 of the frame 41 as shown in Figure 5. It will thusbe apparent that movement of slide 122 will effect one linear directionof movement of the cutter spindle, and movement of the slide will effecta second direction of movement normal to the first direction ofmovement. It will also be apparent that by simultaneous movement of bothslides, at the same rate or at different rates, will efiect angularmovement of the cutter spindle in any direction in a horizontal planewith respect to the fixed axis 44, and thereby renders the cutteradjustable in the same manner as the tracer.

The slide 122 is operatively connected to a yoke member 128, which hasoppositely extending supporting arms 129 journaled in bearing block 130,and 131 journaled in bearing block 132. The arm 131 is connected by apin 133 to a block 134 which is slidable in a recess 135 formed in theslide 122 and held therein by guide members 136 and 137. It will benoted that there is clearance space 138 on opposite sides of the block134 which permits the slide 122 to be moved laterally by the slide 125which is necessary because the block 134 is held against movement inthat direction by the bearing blocks 130 and 132. The yoke member 128 ismoved axially by an eccentric cam 139 journaled in a sliding block 140mounted in the yoke 128. It will be noted that there is a clearance 141at opposite ends of the member 140 whereby rotation of the eccentricwill only cause axial movement of the arms 129 and 131, movement in theother direction amounting to merely lost motion.

The slide 125 is provided with a rack 142, Figure 5, which meshes with apivoted gear member 143 that has gear teeth 144 meshing with a rack bar145 on a slide 146 supported by anti-frictional means 147 in the frame127. A cam block 148 is suitably guided at 149, whereby the block 148has lost motion movement, as shown in Figure 5, in a direction from leftto right, but movement of the block 148 at right angles to thisdirection will cause movement of the rack bar 145 and thereby, throughthe intermediate gear member 143, movement of the slide 125 toward thetop or bottom of the drawing.

I The block 148 has an eccentric earn 150' iournaled therein wherebyrotation of the cam will produce a desired movement in one direction,and a lost motion movement in a direction at right angles thereto. Thecams 139 and 150 are formed on a common member, but in 180 degree phaserelation as shown in Figure 6, although they could be made separately.This member, indicated by the reference numeral 151, is keyed at 152 toa supporting member 153 and secured thereto by a bolt 154. The member153 is confined between guideways 154' and 155 formed on the rotary head117 whereby rotation of the head 117 will, through the member 153, causerotation of the cams 139 and 150. The member 153 is capable of slidingmovement relative to the member 117, and .it is to be noted that whenthe member 153 is in such position that the axis through the center ofthe cams 139 and 150 is co-axially aligned with the axis of rotation ofthe head 117, no lateral displacement of the axis of the cutter spindlewill be effected.

The control member 153 is shifted by a piston 156 which, as shown inFigure 3, is a differential piston having a large face 157 and a smallerface 158 so related that when a. given pump pressure is applied to theface 158 and one-half of that pressure is applied to the face 157, thepiston is in balance. The piston 156 has a piston rod 159 dependingtherefrom, and the lower end of this rod has a square block 169 pinnedthereto, Figure 9, in the opposite sides of which are formed camminggrooves 161 and 162 which extend at an angle of 45 degrees to thedirection of axial movement of the piston rod as shown in Figure 8. Themember 153 has a cross slot 162' out in the reduced upper portionthereof forming guide faces 163 and 164 which bear against the opposingfaces of the square block 160.

This cross slot forms bifurcations 165 and 166, as shown in Figures 7and 9, and camming pins 167 and 168 are driven into these bifurcationsand extend into the cam groove 161 and 162. Thus, any axial movement ofthe piston rod 159 will cause the control member 153 to be moved alongits guideway and thereby shift the axis 169 of the cams 139 and 159relative to the axis 170 of the rotary head 117. The movement of thepiston 156 is controlled by the control valve 91 which, as previouslydescribed, is located in the tracer head as shown in Figure 11. Theoperation of this valve will now be explained;

Referring to the hydraulic diagram in Figure 18, a

source of constant pressure, such as the pump 171 having a relief valve172, is connected through conduit 173 and branch conduit 174 to pressureport 175 in valve sleeve 176. This port is in constant communicationwith an annular groove 177 formed in the piston rod 159 whereby pumppressure always exists in this groove. The conduit 174 has a branchconnection 178 which communicates with the lower cylinder space 179whereby a the pump pressure always exerts an upward force on the face158 of piston 156.

The piston rod 159 has a valve shoulder 130 which moves relative to aport 181 to variably restrict the flow of fluid from the annular groove177 to channel 132. The resistance to flow at the port 181 constitutes are sistance into the channel 182. The channel 182 terminates in a port183 of valve 90, the plunger of which has a shoulder 184 which ismovable relative to the port 183 to variably restrict the flow of fiuidthrough that port into the annular groove 185 formed in the valveplunger 91, which groove is connected to reservoir by line 185'. Theresistance at port 183 constitutes a resistance out of the channel 182,and according to the laws of hydraulics when the resistance in, such asat port 181, is equal to the resistance out," such as the resistance atthe port 183, the pressure in the intermediate space, which in this caseis the channel 182, will be equal to one-half of the incoming pressure.Since the incoming pressure is the pressure of the pump which exists inthe '8 annular groove 177, the pressure in the channel 182 will beone-half of the pump pressure.

The channel 182 is connected to the uppen cylindrical space 186 and actson' the large face 157 of the piston 156, while the full pump pressureacts on the small face 158 of the piston and thereby holds the piston inbalance. With the piston held in balance, any movement caused by thetracer of the shoulder 184 in valve 98 relative to its port 183 willchange the resistance at that port and either increase or decrease theresistance dependent on the direction of movement. This produces acorresponding pressure change in the channel 182, which is greater orless than the constant pump pressure acting on the other side of thepiston 156 whereby the piston 156 will be moved.

Therefore, if the tracer finger 48 should hit a positive abutment duringits traversing movement and should be deflected backward to causemovement of the valve plunger 91, it will cause a corresponding changein pressure on the piston 156 and cause the same to move in' a directionto shift the cutter relative to its supporting frame. This will alwaysbe in the relationship that the cutter will be moved backward in adirection opposite to the direction of feed of its support, and themovement of one will in effect cancel the movement of the other inspace, with the result that the cutter 49 will remain stationary andthereby no overrun to spoil the work.

In the description of Figure ll, it was pointed out that the tracerfinger has an eccentric adjustment, represented by the reference numeral82. Since it is desired that the cutter engage a corresponding point onthe work, it is necessary that the cutter have the same eccentricadjustment relative to its normal position represented by the axis 44.Therefore, the valve is so set in the construction of the device thatthe neutral position or balanced condition of piston 156 is such thatthe cutter has this initial eccentric relation with respect to the axis44.

In the operation of the machine the tracer is held in engagement withthe pattern by a spring and when the tracer arm is at an angle to thepattern surface, such as at an angle of 45 degrees which has been foundvery satisfactory, the tracer valve is in a neutral or stop position.

Referring again to the hydraulic diagram, Figure 18, the tracer valvehas the source of pressure, pump 171, connected to its pressure port187, and there are two exhaust ports 188 and 189 which are connected bychannel 190 to reservoir 191' from which the pump withdraws its fluid.There are two motor ports 190 and 191 in the valve, and these areconnected by channels 192 and 193 to the motor 64 through automaticthrottle valves 194 and 195. These valves operate in the same manner;therefore, description of one should sutfice for both.

Valve 194, for instance, has the channel 192 connected to an end port196 whereby when fluid pressure enters the valve housing it will shiftthe valve plunger 197 to the right, as viewed in Figure 18, and uncoverport 193. The fluid pressure will then continue through line 199 andcheck valve 200 to port 201 located in the opposite end of valve 194 tothereby urge the valve plunger to the left. This action will be aided bythe spring 292 which will cause closure of the port 198. As port 198closes it-creates a resistance to flow in the line 199 and therebycauses a drop in pressure on the right hand end of the plunger. It willbe seen from this action that the pressure in the opposite ends of thevalve will automatically balance and thereby stabilize the position ofthe plunger.

If the channel 192 is connected to exhaust, the pressure of the springwill be greater than the pressure in the left end and the port 198 wouldbe closed. However, it is better that the plunger be in such positionthat the port is just cracked open. To this end the plunger has areduced end 203 which will abut the end of the valve housing to limitthe movement of the plunger to this particular amuse 9 position. Thismaintains the lines full of oil and ready for operation.

The oil passing through (re ports 198 and 198' will pass through lines204 and 285 respectively to ports 206 and 207 of a manual selector valve208. This valve has a plunger 209 which is normally in a downwardposition, as shown, by which the port 296 is connected to port 210, andport 267 is connected to port 211. These ports are connected by channels212 and 213 to the hydraulic motor 64. If the channels were all full ofoil it will now be seen than any movement of the tracer valve plunger 65to either side of its central position will unbalance the pressure inlines 212 and 213 and cause rotation of the hydraulic motor 64 in one orthe other direction and thereby rotation of the tracer head- Should itbe desirable to rotate the tracer head manually as by means of the handwheel 89, the valve plunger 209 is moved upward, therebyshort-circuiting port 211 with port 218 by means of annular groove 214,interdrilled passage 215 in valve plunger 2-39 and annular groove 216.It will be understood that the grooves 214 and 216 will be oppositeports 211 and 210 at this time.

The hydraulic motor 64 is operatively connected to the rotaryservo-valve 113 by means of the telescoping shaft 64. The rotaryservo-valve is connected by hydraulic channels 217 and 218 to the rotaryhydraulic motor 114. This combination of rotary servo-valve and rotarymotor is known in the art and may be the same as that shown in UnitedStates Letters Patent 2,349,641. Pressure to the servo-valve is derivedfrom the pump 171, through line 173 and branch conduit 219, while theother side of the servo-valve is connected by branch line 220 to thecommon return line 190'. It will thus be seen that rotation of thehydraulic motor 64 will automatically cause a similar amount of rotationof the hydraulic motor 114.

The rotary spindle head 117 not only controls the positioning of thecutter spindle through the mechanism described supra, but also directlycontrols the rate and direction of relative movement between the cutterand the work effected by motors 18 and 350. Thus, these three functionsare controlled directly by the rotary position of the single controlmember 117. To this end, the rotary head 117 has a cam 221 fixedthereto, which has a small radius 222, a large radius 223, and crossoverpoints 224 and 225. As shown in Figure 18, reversing valves 226 and 227have valve plungers 228 and 229 which are held in engagement with thecam 221 by springs 230. The valves are arranged 90 degrees apart, andthe valve 226 controls reversible operation of motor 18, while valve 227controls reversible operation of hydraulic motor 350.

When either of the valve plungers 228 or 229 are in engagement with thecrossover points on the cam 221, it is held in a central or neutralposition; and when in engagement with the small radius 222 it ispositioned to one side of its neutral position; and when in engagementwith the large radius 223 it is positioned to the other side of itsneutral position. The valve 226 has motor ports 231 and 232 which areconnected ,by channels 233 and 234 to the hydraulic motor 18, and thevalve 227 has motor ports 235 and 236 which are connected by channels237 and 238 to motor 350. The pressure ports of these valves areconnected to the pump supply line 173, and the exhaust ports 239 and 240respectively are connected by channels 241 and 242 to ports 243 and 244of a balancing valve, indicated generally by the reference numeral 245.The port 243 is connectible by annular groove 246 in valve plunger 247to port 248, and channel 249 to port 250 of a rate valve indicatedgenerally by the reference numeral 251.

Similarly, the port 244 is connected by annular groove 251, valveplunger 252, and channel 253 to port 254 of rate control valve 255. Thevalves 251 and 255 have variable throttle ports 256 and 257 which areconnected to a common branch line 258 leading to the common return line190'. The rate valve 251 has a valve plunger 10 259 on which is formedan annular groove 26!? and a spool 261 which controls the flow from port250 to port 256. A spring 262 holds this plunger in engagement with arate control mechanism 263 which, as shown in Figure 3, is attached tothe rotary member 117.

Similarly, the valve 255 has a plunger 264 on which is formed an annulargroove 265 and a spool 266 which controls the flow from port 254 to theport 257. This plunger is held by a spring 267 in engagement with therate control mechanism 263. These valves are arranged degrees apart, andthe rate control mechanism comprises two rollers 268 and 269 arrangedside by side whereby, as the member 117 rotates, one of the plungersmoves inward while the other moves outward. When the valve plunger 259is in engagement with both rollers, as shown in Figure 18, the port 256is closed, while the plunger 264, being in engagement with only oneroller, the port 257 is open.

It will now be seen that the rate and direction of rotation of thehydraulic motor 18 is controlled by the valves 226 and 251 and that theyoperate upon the return flow from the motors. In other words, the valve226 determines the direction of rotation of the motor 18 like any otherreversing valve, and the flow from this valve passes through line 241and valve 245 in line 249 to the throttle valve 251 whereby the variablethrottling of the port 256 controls the rate. Likewise, the valve 227determines the direction of rotation of the motor 350 and the valve 255determines the rate of operation of the motor through variablethrottling of port 257.

The resultant feed rate, which is the combined effect of motors 18 and350, is controlled by the position of the plungers in valve 245 which isdetermined by the hydraulic pressure in the chamber 270, located betweenthe ends of the plungers 247 and 252. Pressure is supplied to thischamber by pump 171. However, this pressure is a function of the rate offlow to the tracer head hydraulic motor 64, and the valves 194 and 195are the means for deriving this function. As previously described, thevalve 194 has its end portion serially connected in line 212 going toone side of the hydraulic motor 64, and the valve 195 has a portionserially connected with line 213 going to the other side of thehydraulic motor. Thus, regardless of which line is delivering fluid tothe hydraulic motor, there is a valve responsive to that flow.

Both of these valves have another portion which is serially connectedbetween the pump and the hydraulic chamber 270, and their function is toreduce the flow to the chamber 270 when the flow to the hydraulic motor64 is increased. Since there cannot be flow to the motor 64 through bothlines 212 and 213 at the same time, one of the valve ports 198, 198'will be closed and the other open, which means one valve plunger will bein its left hand position and the other plunger shifted to the right.Assume, therefore, that the plunger 197 is shifted to the right, asshown, due to flow in line 192 to the motor 64, the other plunger 271 isto the left, closing port 198, whereby the return flow from the motorpasses through the check valve 272 to line 193 which at this time wouldbe connected to reservoir by the tracer valve.

The pump 171 is connected to port 273 of valve 194, and the plunger 197has a tapered spool 274 in position to restrict the flow to port 275,thus causing a drop in pressure which is reflected in chamber 270,causing plungers 247 and 252 to move toward one another, and therebyrestrict flow through the valve 245 and thus slow the feed rate.

The port 275 is connected by channel 276 to port 277 of valve 195, andplunger 271 of this valve has a tapered spool, controlling port 278, butsince the plunger is to the left, there is free flow through port 278and line 279 to throttle valve 280, which is adjustable to set theoriginal pressure in chamber 270 and thereby determine the normal feedrate. Fluid passes from throttle valve 280, through 1 1 line 281,chamber 270, line 282, to resistance 283 which is connected to thereservoir line 190'.

Since the throttle valve 280 constitutes a resistance in to chamber 270,and the resistance 283 constitutes a resistance out of chamber 270, itbecomes possible to vary the pressure in chamber 270, either by varyingthe setting of the throttle valve, or causing a prior drop in pressureto the fluid supplied to the throttle valve as by means of valves 194and 195.

It is to be noted that if the spool 274 closes port 275, the fluid willbe caused to flow through the resistance 284, thereby insuring thatthere is always a flow through the chamber 270 so as to maintain somedegree of pressure therein.

When valve 194 is to the left and the valve 195 opens to permit flow tothe hydraulic motor 64, it will be obvious that the valve 195 functionsto restrict the flow to chamber 270 and valve 194 permits free flowtherethrough. It will now be seen that each time the tracer valve opensthat there is an automatic reduction in feed rate, and that there is anauomatic repositioning of the cutter spindle with respect to its normalaxis 44 so that it is oriented the same as the tracer, and in thedirection of feed.

It will now be evident that there is a tracer mechanism of a type inwhich the tracer finger is adjustably set ahead in the direction of feedwith respect to the axis of rotation of the tracer head as a referencepoint, but which is actually pivotally connected to the tracer head onthe opposite side of its axis with respect to the tracer finger. Thispivotal connection is also normally on the opposite side of the profileline of the pattern with respect to the tracer finger. The object ofrotating the tracer head is to maintain the imaginary radial line fromthe axis of the tracer head through the axis of the tracer finger alwaysparallel to the pattern, or more precisely, parallel to a tangent of thepattern at the point of contact of the pattern with the tracer. Althoughthis is a very efiicient form of tracer from a tracing actionstandpoint, it will be noted that the tracer finger would not contact apoint on the pattern corresponding to the same point on the work, if thecutter spindle axis was in its normal position, that is, spaced from theaxis of the tracer head equal to the spacing of corresponding points'onthe pattern and work. Therefore, by means of this invention the cutteraxis is positioned ahead of its normal position in the same manner asthe tracer finger by the means shown in Figures 21 and 22, so that itsactual position is oriented with respect to its normal position as areference point. Then the imaginary radius connecting these two axeswill point in the direction of feed. Once this is established, then thespindle head is rotated simultaneously with the tracer head to keep theradii always parallel.

It will now be evident that there is a tracer mechanism of a type inwhich the tracer finger is adjustably set ahead in the direction of feedwith respect to the axis of rotation of the tracer head. This settingahead is necessary to obtain efi'icient tracer action, because unlikeuniversally mounted tracers, this tracer is connected to a rotatableshaft and acts like a crank to rotate the shaft and operate the tracervalve. Therefore, the tracer moves in an arc normal'to the patternsurface in its normal tracing action which it will be noted is crosswiseof the direction of feed. Therefore, since the tracer is set ahead, bymeans of this invention, the cutter is set ahead to compensate itsposition as shown in Figures 21 and 22.

tracer would stall in the corner. To overcome this trouble, as shown inFigures 19 and 20, the arm 86 is provided with another roller 285 whichas shown in Figure 20 rests on an inclined surface 286, formed on theunderside of the handwheel 89. Thus, whenever the tracer finger 48 ismoved backward, that is to the right as viewed in Figure 19 about pin73, the inclined surface 286 acting on roller 285 will cause arm 36 toswing and cause rotation of the block 72 and shaft 67, as shown inFigure 11, to actuate the tracer valve and change the feed direction.

There has thus been provided a new and improved construction whereby acutter and a defiectible tracer finger may be maintained more nearly incontact with corresponding points on the pattern and work throughout aprofiling operation regardless of variations in the deflection ororientation of the tracer finger whereby faster and more accurateprofiling operations may be obtained.

What is claimed is:

1. In a profiling machine having a rotary tracer head and a cutterspindle supported on the machine with their axes in parallel relationand normally spaced in accordance with the spacing of a pattern and workpiece to be engaged thereby, the combination of a tracer finger carrierby the tracer head in co-axial relation therewith, means to laterallyadjust the tracer finger to offset its axis relative to the axis of thetracer head, and means supporting the cutter spindle for lateralmovement relative to the axis of the tracer head whereby the cutterspindle may be laterally offset with respect to its said normal positionan amount equal to said offset of the tracer finger.

2. In a profiling machine having a rotary tracer head mounted thereon,the combination of a cutter spindle mounted on the machine with its axisparallel to the axis of the tracer head and normally spaced therefromequal to the spacing of a pattern and work piece carried by the machine,a tracer finger supported by the tracer head coaxial with the axis ofsaid head, means to adjust the tracer finger eccentrically to the axisof the tracer head a predetermined amount, and means to adjust thecutter spindle eccentrically to its said normal position the samepredetermined amount.

3. In a profiling machine having a rotary tracer head mounted thereon,the combination of a cutter spindle housing mounted on the machine withits spindle axis normally spaced from the axis of the tracer head adistance equal to the spacing of the pattern and work on the machine, atracer finger supported by the tracer head in co-axial relationtherewith, means to adjust the tracer finger radially of theaxis of thetracer head a predetermined amount, and means to adjust the cutterspindle housing radially of the said normal position of the spindle thesame predetermined amount.

4. In a profiling machine having a rotary tracer head mounted thereon,the combination of a cutter spindle housing mounted on themachine withits spindle axis in a normal position spaced from the axis of saidtracer head equal to the spacing of a pattern and work piece to beengaged, a tracer finger mounted on the tracer head with its axisradially adjusted with respect to the axis of the tracer head apredetermined amount, means to adjust the cutter spindle housingradially of said normal position of the spindle axis the samepredetermined amount, and means to etfect rotation of the tracer headand simultaneous rotation of the cutter spindle housing about the normalposition of the spindle axis.

5. In a profiling machine having a rotary tracer head mounted thereon,the combination of a tracer finger.

mounted on said head with its longitudinal axis eccentric to the axis ofrotation of the tracer head a predetermined amount in a radialdirection, a cutter spindle housing containing a cutter spindle mountedon the machine with the axis of the cutter spindle spaced from the axisof the shaman 13 tracer head in a normal position equal to the spacingof the pattern and Work carried by the machine, means to radially adjustsaid spindle with respect to its normal position in a direction parallelto the radial plane of adjustment of the tracer finger and the samepredetermined amount.

6. In a profiling machine having a rotary tracer head mounted thereonand a tracer finger supported by the head with its longitudinal axiseccentrically located with respect to the mis of rotation of said head,the combination of means for supporting the tracer finger foroscillation about an axis normal to its longitudinal axis and normal tothe direction of feed, a cutter spindle supported on the machine withits longitudinal axis in a normal position spaced from the axis of thetracer head equal to the spacing of the pattern and work carried by themachine, means to eccentrically adjust said spindle radially of itsnormal position equal to the eccentric adjustment of the tracer, andmeans to bodily shift the cutter spindle in the plane of feedapproximately equal to the oscillatory movement of the end of the tracerfinger.

7. In a profiling machine having a rotary tracer head and a cutterspindle mounted on the machine in normal positions spaced apart equal tothe spacing of a pattern and work piece mounted on the machine, thecombination of a tracer finger supported on the tracer head, means toelfect a relative feeding movement of the tracer finger and cutterrelative to the patteern and work respectively, means to eccentricallyadjust the tracer finger with respect to the axis of the tracer head andthe cutter spindle with respect to its said normal position in thedirection of the feeding movement, power operable means for rotating thetracer head in response to deflection of the tracer laterally of thedirection of feed, and motion transmitting connections simultaneouslyoperated by said power operable means to adjust the cutter spindlelaterally of the direction of feed to maintain the tracer and cutter incontact with corresponding points on the pattern and work.

8. In a profiling machine having a rotary tracer head and power operablemeans for rotating said head, the combination of a cutter spindle, ahousing supporting the cutter spindle, means supporting the housing inthe machine for bodily rotary movement about an axis eccentric to theaxis of the spindle, and means connecting said power operable means toelfect the rotary movement of said housing.

9. In a profiling machine having a rotary tracer head and power operablemeans for rotating said head, the combination of a cutter spindle, apair of superimposed slides supported in the machine for movement atright angles, a housing for the cutter spindle supported on one of saidslides, and motion transmitting means connecting said power operablemeans to said slides in a manner to efiect bodily, rotary movement ofsaid housing about an axis eccentric to the axis of said spindle.

10. In a profiling machine having a first rotary head, a tracer fingersupported on said head eccentric to the axis of rotation thereof formovement in a first circle, a cutter spindle supported in the machinefor movement in a circle having a radius equal to the radius of saidfirst circle, and a common power means for etlecting circular movementof the tracer finger and the cutter spindle.

11. In a profiling machine having a rotary tracer head and poweroperable means for rotating said head, the combination with a cutterspindle of a second rotary head coupled to said power means forsimultaneous rotation with the tracer head, said second head having aslide movable diametrically of its axis of rotation, an eccentricmechanism carried by said slide and movable therewith to vary the degreeof eccentricity of said mechanism, a cutter spindle supported foruniversal movement in a plane at right angles to its axis includingsupport mechanism, and means coupling said support mechanism to 14 saideccentric mechanism for controlling the position thereof.

12. In a profiling machine having a rotary tracer head, power operablemeans for rotating said head, and a tracer finger supported by the headeccentric to the axis of rotation thereof, the combination of a secondrotary head carrying a slide shiftable diametrically to its axis ofrotation, an eccentric means carried by said slide for shifting therebyto various eccentric positions relative to the axis of rotation of saidhead, means supporting the tracer finger for oscillatory movement aboutan axis normal to the axis of rotation of the tracer head, and automaticservo-control power means responsive to oscillation of the tracer toeifect shifting of said slide.

13. In a profiling machine having a tool and a work support, poweroperable means for eifecting a relative feeding movement between saidsupports and a rotatable tracer head mounted on the tool support andhaving a prescribed radial plane, the rotatable position of whichdetermines the direction of said feeding movement, the combination of atracer finger lying in said plane parallel to the axis of said head,means eccentrically of the axis of said head for pivotally supportingsaid tracer finger for oscillation in said radial plane, a cutterspindle lying parallel to said tracer finger and normally spacedtherefrom a distance equal to the spacing of the pattern and work in themachine, means supporting the said cutter spindle for universal movementlaterally of its axis in a plane normal to its axis, and power operablemeans responsive to oscillatory movement of the tracer finger in saidradial plane for laterally moving the cutter spindle parallel to theplane of feed in amounts substantially equal to the movement of thecontacting end of the tracer.

14. In a profiling machine having a tool and a work support, poweroperable means for effecting a relative feeding movement between saidsupports and a rotatable tracer head mounted on the tool support andhaving a prescribed radial plane, the rotatable position of whichdetermines the direction of said feeding movement, the combination of atracer finger lying in said plane parallel to the axis of said head,means eccentrically of the axis of said head for pivotally supportingsaid tracer finger for oscillation in said radial plane, a cutterspindle lying parallel to said tracer finger and normally spacedtherefrom a distance equal to the spacing of the pattern and work in themachine, means supporting the said cutter spindle for universal movementlaterally of its axis in a plane normal to its axis, and power operablemeans responsive to oscillatory movement of the tracer finger in saidradial plane for laterally moving the cutter spindle parallel to theplane of feed in amounts substantially equal to the movement of thecontacting end of the tracer, said last-named power operable meanscomprising a servo-motor mounted on the tool support, and a servo-valvemounted in the tracer head .and operatively connected to said tracerfinger.

15. In a profiling machine having tool and work supports, power operablemeans for effecting a relative feeding movement between said supportsand a rotatable tracer head mounted on the tool support for controllingthe direction of said feeding movement effected by said power operablemeans, the direction of said feed lying in a prescribed radial plane ofsaid tracer head, the combination of a tracer finger lying in saidradial plane with its longitudinal axis parallel to that of the axis ofthe tracer head, means pivotally supporting the tracer finger foroscillation in said plane, said pivotal supporting means lying eccentricto the axis of the tracer head, a cutter spindle, a pair of superimposedslides supporting said spindle on the tool support, said slides beingmovable normal to each other, a pintle pin carrying cams connected tothe respective slides, means supporting said pintle pin for rectilinearor circular movement, power means responsive to oscillation of saidtracer finger in said radial plane for efiecting said rectilinearmovement, and additional power operable means responsive to lateralmovement of said tracer finger to efiect rotation of said tracer headand circular movement of said pin.

16. In a profiling machine having a tool and a work support, poweroperable means for effecting a relative feeding movement between saidsupports and a rotatable tracer head mounted on the tool support andhaving a prescribed radial plane, the rotatable position of whichdetermines the direction of said feeding movement, the combination of atracer finger lying in said plane parallel to the axis of said head,means eccentrically of the axis of said head for pivotally supportingsaid tracer finger for oscillation in said radial plane, a cutterspindle lying 7 parallel to said'tracer finger and normally spacedtherefrom a distance equal to the spacing of the pattern and work in themachine, means supporting the said cutter spindle for universal movementlaterally of its axis in a plane normal to its axis, and power operablemeans responsive to oscillatory movement of the tracer finger in saidradial plane for laterally moving the cutter spindle parallel to theplane of feed in amounts substantially equal to the movement of thecontacting end of the tracer, said last-named power operable meanscomprising a rotatable head having a fluid reciprocable memberoperatively connected for shifting said cutter spindle, and

a control valve in said tracer head operated by oscillation V of saidtracer in said radial plane for automatically controlling the shiftingof said fluid reciprocal member.

17. In a profiling machine having a tool and work support, poweroperable means for effecting relative feed- 7 ing movement between saidsupports, and a rotary tracer head mounted on the tool support forcontrolling the direction of said feeding movement, the combination of acutter spindle, a pair of superimposed slides supporting said cutterspindle on the tool support, a rotatable head having a radially movablemember operatively connected to said slides, fluid operable means forrotating said tracer head and said rotatable head, a first valve in saidtracer head operated by lateral movement of said tracer finger forgoverning said fluid operable means, a second fluid operable means forshifting said radially movable member, and a second valve in said tracerhead responsive to oscillation radial of the tracer finger to controlsaid second-named fluid operable means.

References Cited in the file of this patent UNlTED STATES PATENTS2,036,362 Sassen et al. Apr. 7, 1936 2,441,915 Abe May 18, 19482,622,616 Humes Dec. 23, 1952

